If it is not leaking at all, I would use a flat head screw driver and some needle nose pliers to straighten out the fins as best you can and continue running it. If you find your radiator overflow hose is spitting coolant more than usual after a good ride then it is probably not getting the air it used to and is overheating. In that case get it replaced. Just keep an eye on it and if it starts burning up coolant, spitting it excessively from the overflow hose, or leaks, replace it.